Clamping device



1950 J. M. HARGRAVE 2,519,652

CLAMPING DEVICE Filed Dec. 31, 1948 .A Tr m 76.

atented Aug. 22, 1956 CLAMPIN'G DEVICE John Morris Hargrave, Cincinnati, Ohio Application December 31, 1948, Serial No. 68,523

' 1'0 Claims. (01. .24253) 1 This invention relates spring actuated clamping devices whereby the pressure exerted by the clamping jaws may be varied by the manipulation of a member which results in the displacement of one or both of the extensions of the spring,

.Hand operated clamps of the nature to be described may be used wherever it is necessary to hold together sheet materials or the like for an indeterminate period of time. Particularly they have widespread application in the aircraft, textile and furniture industries. For example, sheet .material can best be marked or cut' into proper .sizes' while clamped to a pattern or template.

There are many instances in which there are determined advantages in having a clamp in which the degree of tension is adjustable to some extent atleast. For example, for certain purposesa particularly strong tension is necessary and the conventional clamp will not have quite enough-tension for the requirement. On the other hand there are many uses in which the degree of. tension is comparatively unimportant but the conventional tension is too great for-the requirements andplaces an increasing land unnecessary strain on the finger and the hand musclesof the manipulators. In the case of womenv workersparticularly this condition 'results'in complaints and a. certain impairment to provide a'pclarnp in which the original tension may be substantially less than that conventionally provided heretofore but in which'a single simple adjustment increases the tension to a point where 3) it may be substantially more than the conventional. Since the type of clamp to which the invention relates is very simple in construction and is sold 1 in large quantities for a very low price, another bjectpf the invention has been to provide an djustment means which adds little to the cost results in displacement of one extension of the springrelative; to the other extension whereby the pressure exerted at the jaws, of the clamp is .varied.- In each case the spacer is either no'tched or apertured to act as a detent for the ,ring extremity. Ereferably the spring extremto an improvement in 2 ity itself will be deformed at this point of contact to make the operative position of the spacer more stable. This may be accomplished by a crimp in the extremity, as shown by Figures 1-3 and 7-10, or by'other means, e. g., flattening that portion of an otherwise round member;

In all the variations, pressure at the clamping jaws increases 'asthe angle between the spring extensions decreases. In addition all three modifications shown are easily stamped out or machined and economicaltoproduce.

. s Alparticular object of the present. invention is Other advantages of the invention will be more fully apparent from the description of the drawings in which: 7

Figures 1 through 4 demonstrate the preferred embodiment of my invention. Figures 5 and 6 represent one variation and Figures 7 through 11 are directed to a third species. In Figures 1, 3, 5, 7 and 9 parts of the curved portions of handles 29 and 4| are broken away to show details of the respective means for varying the angle between the extremities of the spring.

Figure 1 is a side elevation showing the clamp at the greater of the two possible tensions.

Figure 2 is an end elevation of the clamp as shown in Figure 1.

Figure 3 is a fragmentary side elevation showing the clamp at the lesser of two possible tensions.

Figure 4 is an end elevation of the fragmentary clamp as shown in Figure 3.

Figure 5 is a fragmentary side elevation of a second species of clamp. Dot-dash lines at 38 indicate the effect of removal of member 33.

Figure 6 is an end elevation of the fragmentary clamp as shown in Figure 5.

Figure 7 is a fragmentary side elevation of a third species of clamp, showing the clamp at the greater of two possible tensions:

Figure 8 is an end elevation of the fragmentary clamp as shown by Figure '7.

Figure 9 is afragmentary side elevation showing the clamp at the lesser of two possible tensions. i i

Figure 10 is an end elevation of the fragmentary clamp as shown by Figure 9.

Figure 11 is' a fragmentary section of one handle of the clamp of Figure 9, taken along the line lI-Il.

In Figures 1 through 4', the clamping device is comprised of two interacting arms 26 and 2| which are pivotally secured to each other for hinged movement. In the structure shown a pivot rod 22 joins the 'flanges of the respective arms. The position of rod 22 the embodia ment shown in Figures 1-4 is the same as that of rod 22 in Figures -10, and its exact location with respect to the flanges of the arms and coil spring 23 is most clearly shown in Figure 10. Rod 22 is movable with respect to arm 2| and fixed with respect to arm '20. Material to be engaged is contacted by clamping ends 2 3 and 2% of arms 25] nd 2!. Surrounding rod 22 is a coil spring 23, the extremities of which are extended in the same direction as adjacent handle ends of the arms 25 and 2|. These spring extensions 25 and 26 are adapted to bear against the inner surfaces of arms 20 and 2i causing the arms" handle ends to diverge and the jaw ends' t'o' converge. I d;

The pressure at the clamping ends is varied by the manipulation of a s acer 21, shown here substantially L-shaped in cross-section. Spacer '21 has sides 38 and 30a. Side 30a of spacer-"2i has a detent aperture "28 disposed near the end or "side 30a. This aperture-28 is slightlydarger than a'cross-section" dfextremityfi2d and"is -adapt'ed to receive extremity-25 at itsf'crirnped portion ri I. sueh a der niiay iri'thespring exa tnsion *h'elps prevent "sliding 'or slipping "of spacer 21. U

handle e'n'ds of the clamp, particularly hari'dle 29 ar'e trough like to afiord'both'a 'comfortaible surface for squeezing the handl s-an a recess for spacer 2?. "As shownfsid'e "38d "of spacer 21 is planar; wherea's fs'idesll' of spacer 2? i's arcuafte so that sf-may be retained"against"the "inner surface of "handle 29 when spa'cer "2? operative position, as shown by Figures rule 2.

l'Fuither' nieansfor securing spacer z-raiaegside handle 29' a'renprovided by incorporating in't o *side3'fla a'pair of shoulders '32' and 32a;fwh'i 'ch cooperate with the p'ara'uel ea es'ofnafimee e to prevent iiitivfill'lt of'sfp'a el zl'w he'n'it is in -operativepositioi i. Thus, the 'confi gu'ra'tiohsj of "thesurfacesof spacer '2'i'andha i1d1e2 9 are sufficient to hold the clamp at the increased ten- 'sion"witlrf ut other means of attachment. -Further stabilityis tired-by the deformed portion 3;! "of the spring "extremity cooperating with detent aperture 28. Shoulder and-fiz -result linjsi d'e "steamer-rig slightly wider than handle '(Figure mfwhile side may"preferably'- -be narrower than handle 29 (Figure 4) p The imperative position =ofspacer-'-2;1-- is shown in Figures 3 and 4. This results in the -l'east possible pressure at the clamping :jaws. Due -to the size of aperture-28, spacer- 21 is movable back I 'forth along extremity-25 and=hand1e 29 but its preferable inoperative 'position -iswhat' of Figuress and 4l=in which both ends-of sides 36 and 30a of L-shapedspacer 21 are 'in contact with the inner surfaceof'handle 29,and aper- ;ture =28 isadjacent-crimped portion 3l'of extremity 25. Thus spacer =2'lis capable of'stable positions" when either operative "or inoperative. As shown-- in Figures '3 and '4' spacer 21 presents a smooth exterior surface in its inoperative -position.

To increase the clamping pressure,'i. ez,- to go -fromspac'er Z'ls inoperative positionto its operative position it isonly necessary to'rotatespa'cer 21 about the axis of extremity 25-through an angleof approximately =I80 so that side 30 is in the recess-: providedby the curved haridle' ZS and-shoulders 32 and -32a impede further rotation.

- The inoprativwposition Of-spacer 21 is -pref- 4 ternatively, spacer 21 may be completely re moved by sliding it OK the end of extension 25. In either of these inoperative positions, spring extremity 25 will abut handle 29, or nearly so. The construction shown in Figure 5 is similar to that of Figures 1 through 4 except that the counterpart of L-shaped spacer 2'! is a substantially U-shaped spacer 33 with two detent apertures34 and 35 through which spring extremity "25 isdisposed for maximum cla'mping ipressure. This arrangement is shown by Figures 5 and 6. U-shaped wedge 33 is disposed so that when it "is moved there are two sliding areas of contact asanas1 with the inner surface of handle 29. To decrease the clam-ping pressure, wedge 33 is removed as shown by the arrow in Figure 5. Al- I tern-atively t-he clamping pressure may be varied by the rotation of spacer 33 through an angle of approximately 180. Removal of spacer 33 causes spring extension 25 to revert to the position shown=by 1 dot dash lines 38 in -Figure 5. Aperture: 34 and 35 are larger than thecrosssection of "spring ex tremity' 25 to facilitate in- "troduction, re'moval- 'and rotation of spacer *33. *Like L'-sh'ap ed spacer 21 spacer-e3 may beof-any suitable breadth and thickness. As-Sh'otvnby 'Figurefi it is --prfrably i slightly-narrower "than hand1e 29. 4

Figures 7 through I ll *di'sclosef another? mo'dification. Arms-20 and 2 l, connecting rod zrand spring 23 areconventi'onal elemehts. *'-li7leans for displacing extension 25 is"pi"ovi'ded"'by a"'s'pa'cer 42 -pivotal ly"i noiinte"din "the handle"at" #3;best

disclosed by Figur {11. Thie -mounting ma preferably be supplied by stamping "two hemis'phericholes ir'r Handle 41 5 These hol'es then ac- :commodate ring "Mfal'i integraPpartmf spacer 42. "In FigureQ s acer 42* i ispo'sed" substantially parallel to handle "4 l' "and i the tension of "the"cl'amp is the'lesser"ofthe"two value's'sh'own. {Spacer "42lia sa "notcheddet'enfatw tUre'ceWe, when pivoted, 'ex'tension 25 cf 's ring'23; at a "criinped 'p'o'rtion "3 i of *exte'nsi'on mi-"When spacer 42 is pivoted through "an angle of "sub- 45 stantiauy 90 or "slightly greaterj 'the" displacedment of extension "25;"asshfown" igi'ires V'an'd 8 "resitnts" in a greatertension at "th'e "cramping 'ws; s acer s2mustbeivoteiipeyoiid-a po- "S'1'tion at Tight" an les to extension 2 5" whereby angle a is acute; otherwise, the thfustbf'ex- "tension 25- wi11-'-cause*s acer urtoreyerfitorhe fposition s'hownin' FigureS. SpaCerWZ has a "shoulder 4 S; as" disclosed in Figures '7--'9. "When 'shouider f -l6 abuts theli'ri'ner surface 'ofhandle I angle A is"alilfe'and th diSDtfiitiblf-(Sf' spring "23 and its extensions 25ahd"2'6"is 'stable, as shown in Figures '7 and 8. Similar means-for f'accomplishing this "resultwill"be apparent to those familial hand tools.

'65 a clamp capabie 'drdirrerent *eiamping'pressures *in which om 'orre' of tusspring arms is" displaced. Obviously any "of the means" disclosed may "be provided for-"displacing each -spring "arm -of a given clamp; either 'iindependently' "or coinci- 1 d-ntally; whereby any Of several difiere'nt'clam ing pressures"becornespossible in one "clamping device.

4 Havihg described my invention; I claim:

1'. A clamping" device *adaptable to a plurality or clamping pressuresgsaid device comprising'two pivotally connected arms having handle ends and clamping ends, a spring having elongated extensions diverging the handle ends of said arms and converging the clamping ends of said arms, and a spacer, when in operative position, abutting both the handle end of one of said arms and one of said spring extensions, said spacer movable with respect to said abutting elements whereby manipulation of said spacer varies the displacement of said spring extension relative to said handle.

2. A clamping device adaptable to a plurality of clamping pressures, said device comprising two pivotally connected arms having handle ends and clamping ends, a spring having elongated extensions diverging the handle ends of said arms and converging the clamping ends of said arms, and a rotatable spacer, when in operative position, engaging one of said spring extensions whereby rotation of said spacer varies the displacement of said spring extension relative said handle ends.

3. A clamping device adaptable to a plurality of clamping pressures, said device comprising two pivotally connected arms having handle ends and clamping ends, a spring having elongated extensions diverging the handle ends of said arms and converging the clamping ends of said arms, and a spacer, when in operative position, abutting both the handle end of one of said arms and one of said spring extensions, said spacer rotatable about an axis substantially coincidental with said spring extension whereby rotation of said spacer varies the displacement of said spring extension relative said handle.

4. A clamping device adaptable to a plurality of clamping pressures, said device comprising two pivotally connected arms having handle ends and clamping ends, a spring having elongated 1 extensions diverging the handle ends of said arms and converging the clamping ends of said arms, and a spacer pivotally mounted in the handle end of one of said arms, said spacer, when in operative position, rotatably engaging one of said spring extensions whereby rotation of said spacer variesthe displacement of said spring extension relative said handle ends.

5. A clamping device adaptable to a plurality of clamping pressures, said device comprising two pivotally connected arms having handle ends and clamping ends, a spring having elongated extensions diverging the handle ends of said arms and converging the clamping ends of said arms, and an apertured, substantially U-shaped spacer having legs slidably contacting the inner surface of the handle end of one of said arms,

one extension of said spring residing in the apertures of said spacer whereby said extension is displaced relative to the handle ends.

6. A clamp adaptable to different clamping .0

pressures, said clamp comprising two pivotally connectedarms having handle ends and clamping ends, a spring having elongated extremities bearing against adjacent inner surfaces of the handle ends of said arms, and a substantially L-shaped member apertured adjacent the end of one leg of the L, said member carried by an extremity of said spring whereby rotation of said L-shaped member varies the angle between the extremities of said spring.

7. A clamping device comprising two arms pivotally connected intermediate their ends to provide clamping ends and handle ends, a spring having elongated extensions engaging the inner surfaces of the handle ends and thereby converging the clamping ends, and a spacer inserted between one of said elongated extensions of the spring and the inner surface of one of the handle ends thereby to increase the tension of the spring.

8. A clamping device comprising two arms pivotally connected intermediate their ends to provide clamping'ends and handle ends, a spring having elongated extensions engaging the inner surfaces of the handle ends and thereby converging the clamping ends, and a spacer having one surface thereof configurated to engage the inner surface of one of the handle ends and an opposed surface configurated to engage the extension of the spring disposed adjacent said handle end, said spacer being positioned between said spring extension and said handle end to increase the tension of the spring.

9. A clamping device comprising two arms pivotally connected intermediate their ends to provide clamping ends and handle ends, a spring having elongated extensions engaging the inner surfaces of the handle ends and thereby converging the clamping ends, and a spacer positioned between the extension of the spring and the inner surface of the handle member adjacent thereto for increasing tension of the spring, said spacer being removable from said device and having a surface complementary to the inner surface of the handle member whereby said spacer will be held positioned against said inner surface by the spring extension without other means of attachment.

10. A clamping device comprising two arms pivotally connected intermediate their ends to provide clamping ends and handle ends, a spring having elongated extensions diverging said handle ends, and a spacer positioned between a spring extension and the inner surface of a .handle end adjacent thereto, said spring extension being deformed at the area of contact with said spacer to insure stability of said position.

JOHN MORRIS HARGRAVE.

No references cited. 

